Heat pipes, vapor chambers, and the like are known as cooling devices used to cool heat-generating components such as a central processing unit (CPU) installed in an electronic device (refer to, for example, Japanese Laid-Open Patent Publication Nos. 2015-10765 and 2016-188734). A cooling device includes a working fluid. The cooling device uses phase transition of the working fluid to transfer heat. This cools the heat-generating component to which the cooling device is attached.